Manufacture of hydroxy ethers



Patented July 20, 1954 UNITED STATES PATENT OFFICE signor to The Distillers Company Limited, Edinburgh, Scotland, a British company No Drawing. Application December 4, 1950, Serial No. 199,147

Claims priority, application Great Britain December 8, 1949 19 Claims.

The present invention relates to mono-ethers of octan-diols and in particular to monoctherified derivatives of 2:4:4-trimethylpentandiols.

It is well known that mono-etherified derivatives of alkanols are obtained by the interaction of 1:2-ep0xides with alcohols, and that this reaction may be promoted by catalysts. An epoxide in which the epoxy-group is attached to the first and second atoms in the carbon chain, that is to say an epoxide represented by the general formula RB R -CH2 wherein R signifies an alkyl grouping and R signifies either an alkyl grouping or hydrogen, may give rise by reaction with alcohols to two isomeric mono-etherifled-alkanols represented by the formulae a -g z-ornon and (II) RB R -c-oHioR where R signifies the alkyl grouping corresponding to the reacted alcohol ROI-I. It is further known that, in general, the interaction between such epoxides and alcohols in the presence of catalysts of an acidic nature gives rise to either or usually both of the above-mentioned alkoxyalkanols, and that the reaction in the presence of basic catalysts, on the other hand, gives rise predominantly to the first of the two alkoxyalkanols represented above, that is to say the isomer which the alkoxyl group is attached to the first and the hydroxyl group to the second atom of the carbon chain.

The mono-others of 2:4: l-trimethylpentandiol have not been described before. These hydroxy others are derived from 1:2-epoXy-2:4:4-trimethylpentane of the formula which will be called in the following the epoxide." The epoxide may be prepared by the oxidation in the liquid phase Of v2:4:i.-trimethylpentene-1 by means of molecular oxygen whilst the pH of the liquid reaction mixture is between 5 and 12in 2 accordance with Patent No. 2,650,927 which patent was copending herewith.

The mono-etherified trimethylpentan-diols according to this invention have the formulae In Formula III R signifies an alkyl or a hydroxylated alkyl group whilst in Formula IV R represents an alkyl, a hydroxylated alkyl, or aryl group.

Suitable alcohols for the preparation of ethers of the general Formula III in accordance with this modification of the present invention are primary aliphatic alcohols, such as, methyl, ethyl, propyl and normal butyl alcohol. Secondary alcohols such as isopropanol were found not to react in the desired manner in the presence of acid catalysts. Further suitable alcohols for carrying out the esterification according to the invention are polyhydric alcohols such as ethylene glycol, propane-1:3-diol, 2-methyl-pentane-2 4- diol and glycerol. The products obtained with these polyhydric alcohols are mono-hydroxy alkyl others of the polyhydric alcohol used.

The reaction between the epoxide and the alcohol in the presence of strongly acid catalysts is preferably carried out by slowly adding the epoxide to the alcohol with efi'lcient agitation, the latter to be advantageously in large excess and containing the catalyst in solution. Suitable catalysts for the preparation of said ethers are, for instance, sulphuric acid and phosphoric acid. Of these sulphuric acid is preferred as by this means the reaction proceeds rapidly. A further suitable catalyst is, for instance, boron trifluoride. Hydrochloric acid, on the other hand, was found not to promote the reaction. The reaction is regulated in such a manner that the temperature does not rise substantially above 50 C. When weaker catalysts than sulphuric acid such as phosphoric acid are used however, the temperature is advantageously raised since the reaction proceeds very sluggishly at lower temperatures. For the production of others of the formula according to the present invention, the epoxide is reacted with hydroxy-compounds such as primary fatty alcohols, phenols, cresols, naphthols, such as alphaor beta-naphthol, and polyhydric alcohols in the presence of a basic catalyst. As basic catalysts may be used the hydroxides, alkoxides, phenoxides or naphthoxides of alkali metals such as sodium or potassium, furthermore the alkali metal salts of lower fatty acids or other strongly basic compounds. The reaction in this case is preferably carried out at temperatures exceeding 100 C. such as from 100 to 150 C. with an excess of the hydroxy-compound and when the hydroxy compounds boil at a temperature below that at which the reaction is carried out, preferably in a closed vessel. Higher alcohols such as n-butanol can, however, be reacted at these temperatures in an open vessel, for example by boiling under a reflux condenser. Lower alcohols such as ethanol may alternatively be brought into reaction at reflux temperature, but then on account of the lower temperature thereby attainable it is necessary to employ a greater proportion of catalyst, such as one molecular proportion per molecule of epoxide employed.

Whilst, as has been mentioned above, isopropanel and other secondary alcohols do not furnish appreciable yields of the ether when reacted with the epoxide in the presence of acidic catalysts the etherification proceeds, although slowly and not very satisfactorily, in the presence of alkaline catalysts.

It has been found that when epoxide is reacted with alcohols in the presence of acids almost exclusively ethers according to Formula III are formed. This is in contrast to the general experience according to which a mixture of the two ethers according to the general Formulae I and II results.

The ethers in accordance with this invention and obtained by the reaction of the epoxide with hydroxy compounds may be recovered from the reaction mixture, for instance, by extraction with ether or by fractional distillation, preferably after neutralisation and subsequent washing with water to remove the catalyst.

The etherified alcohols of the general formula in which R, represents a radical corresponding to the alcohol used for etherification, which are the result of the acid catalysed reaction can readily be esterifled and may then be used as plasticisers and solvents. The isomeric compounds with the ether group linked to the terminal carbon atom may be used for example as solvents or brake fluid components.

The following examples serve to illustrate the manner in which the mono-ethers may be prepared from monohydric alcohols:

EXAMPLE 1 50 grams of 1,2-epoxy-2:dz l-trimethylpentane hereafter referred to as the epoxide were slowly added to 250 cc. of mechanically stirred ethanol containing 0.1 gram of sulphuric acid. At the end of the exothermic reaction the acid was neutralized and the mixture fractionally distilled. 19.9 grams of 2-ethoxy-2 4 4-trimethylpentan-1-ol were obtained with some lower boiling fractions. 2-methoxyand 2-n-butoxy-2 4 4-trimethylpentan-l-ol were similarly obtained by using the corresponding alcohols.

EXAMPLE 2 1,000 grams of the epoxide as used in Example 1 were slowly added to 4,000 cc. of methanol which contained 32 cc. of boron trifluoride-diethyl ether complex and was stirred during the addition. At the end of the reaction, the catalyst was destroyed by an excess of aqueous sodium hydroxide, and after evaporation of the meth anol the residue was washed free from inorganic salts with water, dried and fractionally distilled. A yield of 749 grams of 2-methoxy-214z4-trimethylpentan-l-ol was obtained.

EXAMPLE 3 50 grams of the epoxide were allowed to react with 200 cc. of methanol and 1.6 cc. of boron trifluoride etherate as described in Example 2. At the end of the reaction the mixture was boiled under reflux with 5.4 grams of sodium fluoride for half-an-hour and after filtration was then substantially free from boron trifluoride. Fractional distillation then produced firstly unchanged methanol, then unchanged epoxide and by-products and finally 39 grams of 2-methoxy- 2 4 4-trimethyl-pentan-1 -ol.

EXAMPLE 4-.

6 1 grams of the epoxide, 250 cc. of ethyl alcohol and 0.3 cc. of phosphoric acid were boiled under reflux for 5 hours after which, by working up the reaction mixture as described in Example 1, 34.0 grams of 2-ethoxy-2: lz-trimethylpentan-l-ol were recovered from the reaction mixture.

EXAMPLE 5 23 grams of metallic sodium were dissolved in 500 cc. of ethyl alcohol and 128 grams of the epoxide added. After boiling for 3 hours under reflux, the ethyl alcohol was evaporated off, the residue washed with water and the organic product extracted therefrom with ether. By fractional distillation 118 grams of l-ethoxy-Zzzdtrimethyl-pentan-Z-ol were obtained.

The corresponding l-methoxyand l-isopropoxy-Z :4 4-trimethylpentan-2-ol were similarly obtained.

EXAMPLE 6 60 grams of the epoxide and 300 grams of ethanol containing 3 grams of sodium ethoxide were heated in an autoclave to 150 C. for 5 hours. After cooling the alkali was neutralised with acetic acid and the ethyl alcohol evaporated off. The washed residue yielded 53.5 grams of 1- ethoxy-Zzza-trimethylpentan 2 01. A slower conversion was observed at C.

The corresponding isopropoxy compound was similarly obtained although in smaller yield.

EXAMPLE '7 A mixture of 64 grams of the epoxide, 20 grams of sodium hydroxide and 250 cc. of ethyl alcohol was boiled under reflux for 1 hours and worked up as described in Example 5 to give 57 grams of l-ethoxy-2 1 4 4-trimethylpentan-2-ol.

EXAMPLE 8 A mixture of 64 grams of the epoxide, 250 cc. n-butanol and 5 grams of sodium hydroxide was boiled under reflux for 3 hours and similarly worked up as described in Example 5 giving 57.7 grams of 1 n butoxy-2 91:4 trimethylpentan- 2-01.

EXAMPLE 9 To 4'7 grams of phenol in 40 cc. of ethanol and EXAMPLE 6 been proved by elementary analysis, Zerewitinov determination of active hydrogen, and by the detection of two readily esterified and therefore primary hydroxyl groups per molecule.

EXAMPLE 13 128 grams of the epoxide, 150 grams of ethylene glycol and 8 grams of sodium hydroxide were heated for 3 hours at 175 C. in an autoclave with The mixture was diluted 10 a reciprocating stirrer.

A mixture of 64 grams of the epoxide, 200 grams with water and the product isolated by extracof pure lauryl alcohol, and 10 grams of sodium tion with ether and distillation. 87 grams of hydroxide was heated in a stirred autoclave at 1(2 hydroxyethoxy) 2:4:4 trimethylpentan- 175 C. for 3 hours. The product was Washed I 2-01 was obtained. This product generally rewith water and iractionally distilled, yielding 22 sembled in its properties the isomeric product of grams of l-n-dodecyloxy-Z:4:4-trimethylpentan- Example 12 but the two hydroxyl groups in the 2-01. molecule were shown to be difierent from one an- EXAMPLE 11 other in that only one is easily esterified, the

72 grams beta-naphthol was dissolved in 100 y l j prfsumably tefrtiary in accordance cc. of a aqueous sodium hydroxide solution Wlth p1 opmed Structul and 64 grams of 1:2-epoxy-2:4:4-trimethyipen- EXAMPLE 14 tane dissolved in 100 cc. of ethanol was added. 123 grams of the epO d W dded o IniX- The m x ure was boiled under reflux for 24 hours ture of 150 grams of p1.opane 1.3 di01 and 1 aitel Yz t equal Volume of 5 aqueous of boron trifluoride etherate following the prodium ydroxide was added and the p o cedure described in Example 12. The mixture tracted VIM/hr ether. Some unchanged naphthol Was diluted with Water, sufiicient Sodium f? P aqueous phase by "i f droxide added to neutralise the boron trifluoride nat on ide washed e thereal extract was distllled and the product extracted into ether and M23110 lac 111 ram. rig, when the resldue sollditimed. 79 grams of z(z hydroxy n propoxy) S i i figgfig g fi gg g i ig; 2:4:4-trimethylpentan-1-ol were obtained. The

afilu. "4HI"U compound distilled at 136-140 0/3 1 and crystalgg g formed a m n mtmbenzoate 65 lized from light petroleum in asbestos-like needles, melting point 46-47 C. M EXAMPLE 15 The physical properties of the mono-ethers 64 grams of the epoxide were added to a mixfrom monohydric alcohols aceording'to the inventure of 156 grams of 2-methylpentan-2:4-diol and tion are shown in the following table. These 1 cc. of boron trifluoride etherate following the mono ethers are substantially insoluble in water. method of Example 14'. 14 grams of the product Table I spec.

Compound. B. P. 215550 2-lVlethoxy-2'4- -trimethylpentan-Lol. 8386 C./l0 mm 1. 4431 0. 9129 1-Methoxy-2 trimethylpentan-2-ol 65-66" (1/10 mm 1.4294 0.8802 2-Ethoxy-2:4:4-trimethylpentan-l-cl. 9596 C./12 mm 1.4406 0.8994 l-Ethoxy-2:4:4trimethylpentan-2-ol 80 O./20 mm 1.4277 0.8693 1-iso-Propoxy-Z:4:4-tri1nethylpentan- 7983 C./l0mn1 1.4272 0.8008 Z-IEflB iItQX -B'4' -trimetliylpentan-l-ol 114-119" (1/10 mm.. 1.4408 0.8802 l-n-Butoxytrimethylpentan-2-ol. l00-l04 C./l0 mm 1. 1.4335 0.8568 l-Phenoxy-2:4:4-trimethylpentan-2-ol 149 O./l0 mm 1. 5003 0.9786 l-n-l?odecyloxy-2:4:4-trimethylpentan- 168180C./0.5 mm 1.4474

y 0 l36l40 (1/3 M P. 4647 c l aphthoxy-2 4 :4-trimethylpentan- The following examples illustrate the manner in which the mono-ethers of polyhydrie alcohols may be prepared according to the invention.

EXAMPLE 12 128 grams of 1z2-epoxy-2z4z4-trimethylpentane were added slowly to a stirred mixture of 150 grams of ethylene glycol and 1.5 cc. boron trifiuoride etherate, the temperature being kept below C. Sufficient concentrated sodium hydroxide solution was then added to neutralise all the boron trifluoride, and unchanged epoxide and glycol were distilled off up to 120 C./ 10 mm. The residue was taken up in ether, washed with water, dried and after removal of the solvent was dis tilled in vacuo. '77 grams of 2(2'-hydroxyethoxy) -2 :4: 4-trimethylpentan-1-ol was thereby obtained. The product forms a bis-alphagamma-gamma-trimethyl-valerate, B. P. 160- 164 C./2/L and a bis-3:5-dinitrobenzoate, M. P. 107-109 C.: the structure of the product has identified as 2-4-hydroxy-4-methyl-2-pentyl oxy)--2:4:4-trimethyipentan-l-ol was obtained; it contained one easily esterified and one dimcultly esterified and therefore tertiary hydroxyl group per molecule.

EXAMPLE 16 128 grams of the epoxide were added to 300 grams of glycerol and 2 cc. of boron trifluoride etherate following the procedure of Example 14.

Table II Refract.

Solubility Compound B. P 11118 12 X in Water 2-(2-hydroxyethoxy)-224:4-trimeth- 114116 G./0.5 mm. 1.4597 slight.

pentan-l-ol. l-(2-hydroxyethoxy)-2:4:4-trimeth- 97 CJOA mm 1. 4541 Do.

ylpcntan-Q-oL 2-(2-hydroxy-n-propoxy)-2:4:4-tri- 130-134 C./0.5 mm 1. 4623 insoluble.

methylpentan-l-ol. 2-(4-hydroxy-4-methyl-2-pentyll131l5 O./0.1 mm.. 1.4548 Do.

oxy)-2: 4 4-trimcthyl-pentan-l-ol. 2 (2 :3 dihydroxy n propoxy) lei-158 C./0.3 mm 1. 4688 soluble.

2 4 :4-trimcthyl-p entan-l-ol.

I claim: sisting of sulphuric acid, phosphoric acid and 1. Ethers of the general formula selected from the group consisting of where R is a radical selected from the group consisting of alkyl and a hydroxylated alkyl radical and R is a radical selected from the group consisting of alkyl, aryl and hydroxylated alkyl radicals.

2. A process which comprises reacting 1:2 epoxy-2: lze-trimethylpentane in the presence of a catalyst with a hydroxy compound to pro duce an ether of the general formula selected from the group consisting of CH3 CH3 CH3( 3OH-z-CHaOH CH2 OR and ( CH2 CHI OHr--CHZ-O-CHZOR' H: OH

where R is a radical selected from the group consisting of alkyl and a hydroxylated alkyl radical and R is a radical selected from the group consisting of alkyl, aryl and hydroxylated alkyl radicals, said hydroxy compound for producing ether (A) being selected from the group consisting of hydroxy compounds of an alkyl and a hydroxylated alkyl radical, and said hydroxy compound for producing ether (B) being selected from the group consisting of hydroxy compounds of an alkyl, an aryl, and a hydroxylated alkyl radical.

3. A process which comprises reacting 1:2- epoxy-2zz-trimethylpentane in the presence of an acidic catalyst with a hydroxylated compound selected from the group consisting of monohydric primary aliphatic and polyhydric aliphatic alcohols to produce an ether having the formula 4. Process as claimed in claim 3 wherein the acidic catalyst is selected from the group conboron trifluoride.

5. Process as claimed in claim 3 which comprises carrying out the etherification at a temperature of about 50 C.

6. A process which comprises reacting 1:2- epoxy-2: lA-trimethylpentane with a hydroxy compound selected from the group consisting of monohydric aliphatic alcohols, polyhydric aliphatic-alcohols, phenols and naphthols in the presence of a basic catalyst to produce an ether of the formula CH3 CH3 where R, is a radical selected from the group consisting of alkyl, aryl and hydroxylated alkyl radicals, said hydroxylated alkyl radicals being selected from the group consisting of an alkyl and a hydroxylated alkyl radical.

'7. Process as claimed in claim 6 which cornprises carrying out the condensation at a temperature between 60 and 250 C.

8. Process as claimed in claim 6 wherein alkali metal phenoxide is used as catalyst in the etherification with a phenol.

9. Process as claimed in claim 6 which comprises using alkali metal naphthoxide for the etherification with a naphthol.

10. A process in accordance with claim 6 in which the alcohol is methyl alcohol.

11. A process in accordance with claim 6 in which the alcohol is ethyl alcohol.

12. A process in accordance with claim 6 in which the alcohol is lauryl alcohol.

13. A process in accordance with claim 6 in which the alcohol is ethylene glycol.

14. A process in accordance with claim 6 in which the alcohol is propane-1:3 diol.

15. The compound 2-methoxy-2wlz4-trimethylpentan-l-ol.

16. The compound 1-ethoxy-2:ez l-trimethylpentan-Z-ol.

17. The compound l-n-dodecyloxy-2: LA-trimethylpentan-Z-ol.

18. The compound 2-(2'-hydroxyethoxy)- 2 4:4-trimethylpentan-l-ol.

19. The compound 1-(2'-hydroxyethoxy)- 2 4 l-trimethylpentan-Z-ol.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,327,053 Marple et a1. Aug. 17, 1943 2,380,185 Marple et al. July 10, 1.945 2,491,533 Swern Dec. 20, 1949 

1. ETHERS OF THE GENERAL FORMULA SELECTED FROM THE GROUP CONSISTING OF 